In general, the three primary colors of light such as red (R), green (G) and blue (B) are required in implementing a full color image. The three primary colors may be obtained by various methods, and in particular, a method using light, which has a very wide expression range of colors and the highest color sensitivity, is most commonly used. Therefore, there have been many laser projection displays using the method in the prior art.
A laser projection display largely includes respective laser light sources generating the three primary colors, a spatial modulator spatial-modulating laser generated from the respective laser light sources, diverse forms of optical systems, and drivers driving and controlling thereof. Although red light and blue light have been generally generated using a semiconductor laser, however, green light has not been directly generated using the semiconductor laser. Instead, as described in the related art, infrared light is generated by pumping a predetermined wavelength of light and is then converted into secondary harmonic light to generate green light.
With the recent distribution of various types of portable electronic machines, there is a demand for more compact laser projection displays. However, in order to implement the compact laser projection displays, the problem of low voltage should be solved. Also, a conventional light source for generating green light has been developed to be used as a pointer, such that is is very sensitive to temperature change. As a result, the operational characteristics of the light source are changed. In order to generate stable green light without being affected by temperature change, a thermo electric cooler (TEC) is provided and the TEC is generally mounted on the exterior of the portable electronic machines, while considering the problem of the size. However, the exterior shape of the TEC is still insufficient for providing stable temperature and fails to solve the problem of the size.
Meanwhile, the conventional module generating green light has a difficulty in maintaining polarization of the green light, such that it is almost in a non-polarized state.